1. Field of the Invention
The present invention relates to diagnosis and treatment of vulnerable plaque in blood vessels.
2. Description of the Prior Art
Current vessel treatments include angioplasty and placement of stents to treat a blockage of a vessel. A problem with current treatments is recurrent stenosis that may result in subsequent procedures. Vulnerable plaque rupture is believed to be the cause of death in a large percentage of patients suffering heart attack and stroke. Detection of vulnerable plaque is problematic because the vulnerable plaque may not be associated with arterial blockage.
Accordingly, there exists a need for an apparatus and related techniques for diagnosing and treating vulnerable plaque in blood vessels. The present invention satisfies these needs and provides further related advantages.
The present invention may be embodied in a method, and related apparatus, for elimination of vulnerable plaque in a vessel. In the method, vulnerable plaque is detected in the vessel, and the detected vulnerable plaque in the vessel is treated using cryoablation.
In more detailed features of the invention, the vulnerable plaque may be detected in the vessel based on an increase in vessel wall temperature indicative of vulnerable plaque. Treatment of the detected vulnerable plaque may include spraying the vulnerable plaque with a cooled fluid, such as saline having a temperature of about 0xc2x0 C. The vulnerable plaque may be ablated using a subzero or cryogenic fluid.
The present invention also may be embodied in a catheter for vessel treatment having a temperature sensor for detecting a temperature increase on a vessel wall indicative of vulnerable plaque, and a balloon for performing cryoablation on the vessel wall for vulnerable plaque treatment. The temperature sensor may be a thermal sensing wire on a surface of the balloon, a thermal sensing polymer on a surface of the balloon, or an optical thermometer, such as an infrared thermometer, that is placed at a distal tip of the balloon and joined to a guidewire.
In more detailed features of the invention, the balloon may have multiple chambers, such as a first chamber for centering the catheter within the vessel, a second chamber for performing the cyroablation, and a third chamber for allowing blood to flow in the vessel past the catheter. The vessel may be a heart vessel or a corotid artery. The catheter may further include a first lumen for supporting the balloon, a second lumen for providing cryogenic fluid to the balloon to inflate the balloon, and a third lumen for returning cryogentic fluid from the balloon. The catheter may also include a larger marker near a distal end of the catheter for joining together the first lumen and the second lumen, and a smaller marker at a proximal area of the catheter for joining together the first lumen, the second lumen, and the third lumen